Nine SpaceX Merlin engines power the Falcon 9 first stage with 85,000 lbs-f sea level thrust per engine for a total thrust on liftoff of 765,000 pounds. The Falcon 9 tank walls and domes are made from aluminum 2219, the same alloy used by the Saturn V. However, we make use of an all friction stir welded tank, the highest strength and most reliable welding technique available. Like Falcon 1, the interstage, which connects the upper and lower stage for Falcon 9, is a carbon fiber honeycomb structure. The separation system is a larger version of what was used on Falcon 1 – pneumatic pushers with pyrotechnic release bolts.

Rocketplane Kistler, meanwhile, would receive $207 million to help complete the K-1 reusable rocket and develop a cargo module that, like Dragon, could later be modified to carry astronauts to the space station.

SpaceX and Rocketplane Kistler are expected to conduct three flight demonstrations before 2010 to prove that they have what it takes to safely deliver pressurized and unpressurized cargo to the International Space Station. At that point, NASA intends to conduct a second open competition for service contracts to supply the space station.

The Kistler K-1 is a two-stage vehicle designed for full reusability. It is 121 feet (36.9 m) in overall length, 22 feet (6.7 m) in diameter and weighs 841,000 pounds (382,300 kg) at liftoff. The vehicle, powered by liquid-propellant engines from Aerojet, is designed to be reused 100 times. It is planned to be able to launch 2500-4000kg.

That competition, Horowitz said, will be open to all comers, not just SpaceX and Rocketplane Kistler.